In order to measure the depth of water, a pressure gauge is generally used. Such a pressure gauge is attached to the outer surface of a structure (including underwater moving body), and receives pressure, which is received by the structure, at the same time, thereby measuring the underwater pressure.
However, when disturbances (vortexes or strong tidal currents generated by the operation of a thruster) are applied to the structure, the water pressure becomes relatively low or high, and as a result the measured depth of water may differ from the actual depth of water at which the equipment exists. That is, there is a problem in that since the accurate water pressure cannot be measured due to the disturbances, the accurate depth of water cannot be determined.
As a prior art, Korean Patent No. 10-1158413 (published on Jun. 22, 2012) discloses a radiation-resistant Linear Variable Differential Transform (LVDT) for pressure measurement. The radiation-resistant LVDT for pressure measurement is adapted to measure pressure under a high-temperature and high-pressure condition. However, since there is not provided means for removing the low-frequency and high-frequency of disturbances that are generated from the outside of the structure, it is difficult to perform stable pressure measurement.